An aspect of vehicle handling receiving increased recent attention is vehicle rollover. Some recently produced or proposed active chassis control systems have sufficient control authority (in terms of ability to affect vehicle path or roll angle) to be potentially useful in preventing some types of rollovers. To prevent rollovers, these systems need to be activated when the roll angle is relatively small, roughly corresponding to the two wheel lift off condition. In order for these systems to operate properly, it is advantageous to know the roll angle, as well as roll rate, of the vehicle body with respect to the road. While the absolute roll rate can be measured directly by a sensor, the roll angle and, to a lesser extent, roll rate with respect to the road need to be estimated. Algorithms exist for predicting impending rollover by estimating roll angle for the purpose of deploying supplementary restraint systems (e.g. side curtains or side airbags). But these algorithms are designed to predict roll angles close to the critical value, corresponding to a static marginally stable condition, which is about 45 degrees. They may not be accurate for roll angle magnitudes in the range of approximately 5 to 20 degrees, which is of primary interest in rollover prevention.